[PATCH rtw-next 3/3] wifi: rtw89: disable CSI STBC for VHT 160MHz

[Ping-Ke Shih <pkshih@realtek.com>]

From: Dian-Syuan Yang <dian_syuan0116@realtek.com>

Fix interoperability problem where CSI feedback with STBC enabled at
VHT 160MHz BW cannot be properly decoded by certain APs, causing CSI
reports to be rejected. This problem is specific to Wi-Fi 7 chips,
as Wi-Fi 6 defaults to 20MHz CSI BW. Therefore, disable STBC encoding
for CSI transmission in VHT 160MHz mode to ensure CSI feedback is
accepted by these APs and maintain smooth throughput.

Signed-off-by: Dian-Syuan Yang <dian_syuan0116@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
---
 drivers/net/wireless/realtek/rtw89/mac_be.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/net/wireless/realtek/rtw89/mac_be.c b/drivers/net/wireless/realtek/rtw89/mac_be.c
index 39a28fd27412..4d61313a2a84 100644
--- a/drivers/net/wireless/realtek/rtw89/mac_be.c
+++ b/drivers/net/wireless/realtek/rtw89/mac_be.c
@@ -2750,6 +2750,10 @@ static int rtw89_mac_set_csi_para_reg_be(struct rtw89_dev *rtwdev,
 		sound_dim = min(sound_dim, t);
 	}
 
+	/* Disable stbc_en in VHT 160MHz to avoid IOT issues with certain APs */
+	if (link_sta->vht_cap.cap & IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160MHZ)
+		stbc_en = 0;
+
 	nc = min(nc, sound_dim);
 	nr = min(nr, sound_dim);
 
-- 
2.25.1